Medical system, method and apparatus employing MEMS

ABSTRACT

A biological suspension processing system is disclosed that may include a suspension treatment device for treating one or more components of a biological suspension, a first fluid flow path for introducing a suspension into the treatment device and a second fluid flow path for withdrawing a constituent of the suspension from the device. At least on microelectromechanical (MEM) sensor communicates with one of the fluid flow paths for sensing a selected characteristic of the fluid therewith. The MEM sensor may be located elsewhere, such as on a container or bag and communicate with the interior for sensing a characteristic of the fluid contained therein. A wide variety of characteristics may be sensed, such as flow rate, pH, cell type, cell antigenicity, DNA, viral or bacterial presence, cholesterol, hematocrit, cell concentration, cell count, partial pressure, pathogen presence, or viscosity.

This application claims the benefit of provisional application No.60/216,640, filed on Jul. 7, 2000.

The present invention relates generally to medical systems, methods andapparatus for processing biological suspensions including, but notlimited to, blood. More specifically, the present invention relates tonovel medical systems, methods and apparatus (for processing biologicalsuspensions) that employ microelectromechanical systems (“MEMS”) assensors, detectors or other elements for improving product quality,purity, consistency, characterization, and/or production.

The present invention is described below in connection with theprocessing of blood and blood components, a field in which it isexpected to find substantial application and benefit. However, it shouldbe understood that the present invention is not limited to blood orblood component processing and may be employed in connection with theprocessing of other biological suspensions, for example, bone marrow orcell growth media.

The processing of blood and blood components has taken on increasedsignificance in recent years due to the increased demand for blood andblood components for therapeutic application. Blood is a suspension ofcells or cell fragments that are suspended in a liquid. The cellsinclude red cells, for carrying oxygen from the lungs to the muscles andreturning carbon dioxide from the muscles to the lungs, white cells, forfighting infection, and platelets, for clotting. The cells are suspendedin a liquid called plasma, and the plasma itself has constituents thatcan be separated through a process called fractionation. For purposes ofthis description, blood “component” and blood “constituent” are usedinterchangeably.

Red cells are typically needed by patients suffering from significantblood loss. Platelets are required by many patients undergoingchemotherapy or radiation treatment, which reduces the ability of thebody to make new blood cells (and platelets are among the shortest-livedblood cell). Plasma may be administered to patients for a variety ofreasons, or may be subjected to further fractionation to isolate andconcentrate certain blood proteins.

As the demand for blood components has increased, it has become routineto separate collected blood into its constituent parts so that only therequired constituent is given to the patient, and the other componentsor constituents remain available for other patients, or are returned tothe donor. A term commonly used for separation of blood into one or moreconstituents is “apheresis.” Apheresis may be done manually, after wholeblood is collected, or it may be carried out in an automated orsemi-automated procedure.

Automated apheresis typically employs a reusable device or instrumentand a disposable, single use tubing set through which the blood flowsfor processing. The collected constituent, such as platelets, red cellsor plasma, is typically withdrawn and directed to a storage container,or collected within a container inside the device, and the other bloodconstituents are either returned to the donor or separately withdrawnand stored for other uses. A variety of devices, based on differentprinciples, have been used in automated apheresis. The most commondevices are based on centrifugation principles, and separate the bloodcomponents based on their different densities. The CS-3000® and Amicusseparators by Baxter Healthcare Corporation of Deerfield, Ill., and theTrima® and Spectra® separators by Gambro BCT of Lakewood, Colo., areexamples of centrifugal blood separators or apheresis devices. TheAutopheresis-C separator by Baxter Healthcare Corporation is anothertype of apheresis device. It operates on a principle of membraneseparation using Taylor vortices, which is much different than theabove-identified centrifugation devices. The present invention is notlimited to a particular treatment device or principle of operation, andmay be of significant benefit in any of these and other blood orsuspension treatment devices.

In addition to collection of blood constituents from healthy donors, thesame equipment and processes may be used therapeutically, to treat illpatients. For example, when it is believed that a patient may benefit bydepleting the amount of white cells or by removing plasma, the sameequipment used with donors may be used to collect those constituentsfrom patients, returning the remainder of the blood to the patient.Blood processing as a therapeutic procedure for a wide variety ofconditions has also grown in recent years.

Although blood constituent collection or depletion has been performedfor many years, and advances have been made, there remain significantareas where further improvements are needed. One area where there issignificant need for improvement is in reducing the potential for humanerror in the collection and testing of blood components. In a normalplatelet collection procedure, for example, a number of tests areconducted on the blood withdrawn from the donor and on the plateletconcentrate that is collected. For example, an incoming blood sample maybe withdrawn from the tubing set and sent to a laboratory for testingregarding platelet count, the presence of pathogens, blood type, and avariety of other tests.

A sample of the collected blood constituent may also be subjected tosimilar tests. For platelets, for example, the amount of collectedplatelets is a particularly important number, because a certain amountof platelets (4×10¹¹) is usually necessary to constitute a standard“dose” or “unit” of platelets. In addition to determining the number(or, alternatively, the density) of platelets collected, the collectedplatelet product also may be tested for the presence of white cells,which are a suggested source of adverse reactions in some patients.

Many of these tests either are not conducted at the same place the bloodcomponent is collected or require 24-48 hours to complete. Great caremust be taken, and numerous administrative steps completed, to assurethat the sample is properly traceable to the collected blood product,and that the laboratory results are properly recorded in connection withthe particular blood product collected. Notwithstanding such care,because of the number of individuals and steps involved, the risk ofhuman error in this process is real, even if small. Accordingly there isa continuing need for advances that reduce the amount of human handlingand intervention required, and thus the potential for error as well asthe cost associated with collecting and testing blood constituents. Morespecifically, there is a need for collection or treatment systems thatprovide a product, such as blood platelets, red cells or plasma, whichis fully or partially characterized, such as by cell count, pathogenpresence, white cell count, blood type, et cetera, with minimum humanintervention and with minimum need for testing procedures that separatethe testing from the treatment process itself and thereby introduceopportunity for human error.

Because the demand for blood components is not constant, it also is notunusual for certain blood constituents to be wasted due to outdatingbefore they are used. Although red cells, which may be refrigerated andstored for lengthier periods of time, blood platelets are normallystored at room temperature, and have a limited shelf life of about 5-7days under the best of circumstances. Both, however, have limited shelflife, and, as a result, it is not uncommon for a significant amount ofcollected blood constituent product to be wasted because it is not usedwithin the allowed shelf life period. Thus, in light of the limiteddonor pool that is available to contribute platelets and other bloodcomponents, there is a need for better efficiencies in collecting andusing blood components.

In addition to the above, there is a continuing need for devices thatmake the collection process itself more efficient. For example, thehematocrit and platelet count of a donor may be of significant value intailoring or optimizing the collection procedure to obtain the desiredamount of the collected product, in the desired amount of time, with thedesired amount of purity or freedom from undesirable components, andwith minimum adverse effects to the donor or patient. Although thedonor's hematocrit may be measured reasonably easily prior to acollection procedure, platelet count is an expensive and time consumingprocedure, and typically is not done prior to the procedure. In mostplatelet collection procedures, the best available information is anestimated platelet count, based on an average of prior donations, whichcan vary widely. Accordingly, there is a need for more currentinformation that can be used to optimize the collection procedure.

In summary, there is a continuing need for improvement in providingblood constituents regarding (1) the consistency of the collectedproduct, for example in terms of the yield or amount of constituentcollected and available for transfusion or the quality (e.g., viability)of the blood constituent collected, (2) the purity of the collectedproduct, for example the absence of undesirable contaminants and betterassurance of completion of all the necessary testing with reduced chanceof human error, (3) the efficiency of collection and usage of collectedblood constituent, (4) the cost and error potential in the collectionand associated testing and administrative burden and (5) the safetyafforded to the donor.

Within the past decade significant progress has also been made in thefield of microelectromechanical systems (MEMS). MEMS is a class ofsystems that are physically very, very small. These systems typically,but not exclusively, have both electrical and mechanical or opticalcomponents. Modified integrated circuit fabrication techniques andmaterials were originally used to create these very small devices orsystems, but currently many more fabrication techniques and materialsare available.

MEMS devices have been conceived for a variety of sensing and actuatingfunctions. MEMS devices have been conceived for typing blood, countingcells, identifying DNA, performing chemical assays, measuring pH,sensing partial pressures, and performing a wide variety of otherprocedures and tests. Recently, various manufacturers have even claimedto have developed a “lab on a chip” that is suitable for carrying out avariety of blood or blood constituent assays or tests. However, progressin integrating MEMS devices into pre-existing medical procedures toenhance performance and reduce potential for human error has beenlimited.

SUMMARY

To achieve one or more of the above objectives, the present inventionemploys a MEMS sensor in a system for processing a biologicalsuspension, for example blood, in a treatment device, wherein the MEMSsensor is employed to sense one or more fluid characteristics of fluidflowing into or from the treatment device. More specifically, thepresent invention may be embodied in a biological suspension processingsystem comprising a suspension treatment device for treating one or morecomponents of a biological suspension, a first fluid flow pathcommunicating with the treatment device for introducing a suspensioninto the treatment device, and a second fluid flow path communicatingwith the treatment device for withdrawing a constituent of thesuspension from the treatment device. In accordance with the presentinvention, at least one microelectromechanical (MEMS) sensorcommunicates with one of said fluid flow paths for sensing a selectedcharacteristic of the fluid within the flow path. The treatment devicemay be an apheresis device for separating and collecting one or moreblood constituents, but in its broader aspects, the present invention isnot necessarily limited to a particular suspension treatment device orto a particular apheresis device or separator.

Turning back to aspects of the present invention, the MEMS sensor may beoperable to sense a characteristic such as, for example, one of thoseselected from the group consisting of flow rate, pH, cell type, cellantigenicity, cell concentration, cell count, viscosity, cholesterol,hematocrit, DNA, viral or bacterial presence, pathogen presence, and/orpartial pressure of a selected gas or other characteristics.

To aid in control of the system, the sensor may communicate with thefirst fluid flow path and generate a signal responsive to one or moreselected characteristics of the fluid (e.g. platelet count) in the firstfluid flow path. The suspension treatment device may include acontroller adapted, to receive the sensor signal and to control thetreatment device in response to the signal. This system could be used,for example, to optimize the treatment procedure time, to provide a moreconsistent product, to provide a product that has a certain minimumquantity of suspension constituent, or to better safeguard patientaffects. A sensor may also communicate with the second fluid flow path,which conducts the fluid being withdrawn from the treatment device, forexample to count desired or non-desired components, such as platelets orwhite cells, or for other desired purposes.

For even better control the system may include sensor adapted to sense aselected characteristic a plurality of times at discrete intervals. Thissensor may generate a signal each time it senses the characteristic, andthe suspension treatment device may include a controller that is adaptedto receive the sensor signal and to control the treatment device inresponse thereto. Thus, periodic sensing may be used to better optimizeor improve the treatment procedure over all or part of the treatmentprocedure. For example, the sensor may communicate with the second fluidflow path and sense the approximate quantity or concentration of aselected cell, with the controller controlling the system to collect adesired quantity of the selected cell, or alternatively, to reduce thecollected amount of the selected cell.

The system may further comprise a container communicating with thesecond fluid flow path for receiving the withdrawn constituent, with thesystem being adapted to provide tracking information for associatingwith the container the particular characteristic sensed by at least onesensor. A machine readable or human readable data storage media may becarried by the container to store information regarding the particularcharacteristics sensed by at least one sensor. The data storage media isnot limited to a particular type, and may comprise a graphic indicatorsuch as a bar code label on the container, an electronic data storagedevice, such as one with a non-volatile semiconductor memory, or an iconor other graphic carried by the container representative of the sensedcharacteristic. This tracking may be entirely carried out by the system,thereby reducing the possibility of human error in mishandling of thesample or information.

When the suspension includes one or more blood components and the bloodcomponent withdrawn is a cellular component, the system may include acontainer for storing the cellular component withdrawn, and the datastorage media may include data regarding, for example, the type,quality, purity, quantity and/or concentration of the cellular componentin the container. More specifically, the system may include a firstsensor communicating with the first fluid flow path and a second sensorcommunicating with the second flow path and the treatment device maycomprise an apheresis device. When the suspension comprises whole blood,the first sensor may sense inter alia, platelets to determine a plateletcount in the suspension introduced into the apheresis device and thesecond sensor may sense inter alia, platelets withdrawn to determine aplatelet count in the second flow path. A container communicating withthe second flow path may be provided to store the blood plateletswithdrawn, and the system may further comprises machine readable orhuman readable data storage media carried by the container for storinginformation regarding platelet count sensed by one or both of saidsensors. To reduce the number of human interventions required, thesystem may itself include a data recording device for receiving a signalfrom one or more of the sensors and recording the data regarding thesensed characteristic. The data recording device may be a printer forprinting a human or machine readable report of the characteristicsensed, such as directly on the container or on a label affixed to thecontainer. Alternatively, the container may carry a machine readableelectronic data storage device, and the data recording device be adaptedto transfer data regarding the selected characteristic sensed by thesensor to the electronic data storage device. An electronic data storagedevice may preferably comprise a non-volatile semiconductor memory, or“write once, reads many times” memory so that the data is notinadvertently lost or destroyed by power loss. In other words, a memoryor processing chip may be added to the blood constituent storagecontainer, such as permanently mounted in the tail flap of thecontainer, with a non-volatile memory, for receiving and storing datafor later access by the appropriate electronic reading instrument.

The blood component storage container also may include amicroelectromechanical sensor carried by the container and communicatingwith the container compartment for sensing a selected characteristic,for example just before administration to a patient, of the bloodcomponent received or stored therein. Such a sensor similarly mayinclude a non-volatile semiconductor memory or so-called “write once,read many times” data storage.

In accordance with another aspect, the present invention may be directedto a blood processing system for providing a characterized bloodconstituent product in which the system comprises: an apheresis devicefor separating one or more desired cellular blood constituents from asuspension comprising whole blood, a first fluid flow path communicatingwith the apheresis device for introducing a suspension comprising wholeblood into the device, a second fluid flow path communicating with theapheresis device for withdrawing at least one desired cellular bloodconstituent from the device, a container communicating with the secondfluid flow path for receiving the blood constituent withdrawn from theapheresis device, machine readable or human readable data storage mediacarried by the container, at least one microelectromechanical sensorcommunicating with the first fluid flow path for sensing at least onecharacteristic of the whole blood and for generating at least oneelectrical signal responsive to such sensing, at least onemicroelectromechanical sensor communicating with the second flow pathfor sensing the quantity of cellular blood constituent withdrawn fromthe apheresis device and for generating an electrical signal responsiveto such sensing, a data recorder adapted to receive the electricalsignals from the sensors and to record data regarding the sensedcharacteristics on the data storage media, whereby a user may readilyidentify the sensed characteristic regarding the whole blood and thequantity of the desired cellular constituent in the container with aminimum of human intervention.

This system may further include a sensor communicating with the secondfluid flow path for sensing the quantity of a non-desired biologicconstituent in the flow path and generating an electrical signalresponsive to the quantity, the data recorder being adapted to receivesuch signal and record data regarding the quantity of non-desiredcellular constituent in the data storage media for access by a user ofthe product in the container. The non-desired biologic component may bea viral constituent, or a cellular constituent, such as white cells.

As before, the system may include a controller adapted to receive thesignals from the sensors communicating with the first and second fluidflow paths and to control the apheresis device in response to one ormore of such signals to provide a desired cellular blood constituentproduct characterized by data recorded in the data storage media inaccordance with characteristics sensed by the sensors. The data storagemedia may comprise machine readable graphics carried on the container,for example, a bar code. The system may also, when withdrawing bloodfrom a donor or patient, for example, generate a human-readable reportfor the donor or patient containing selected data regarding one or moreof the sensed characteristics.

In accordance with another aspect of the present invention, a biologicalsuspension processing system may be provided which includes: a bloodtreatment device for treating one or more components of a biologicalsuspension, a human subject, a first fluid flow path communicating withthe vascular system of the human subject and the treatment device forintroducing blood from the human subject into the treatment device, asecond fluid flow path communicating with the treatment device forwithdrawing a constituent of the blood from the treatment device, athird fluid flow path communicating with the treatment device fromwithdrawing another constituent of the blood from the treatment device,and at least one microelectromechanical sensor communicating with one ofsaid fluid flow paths for sensing a selected characteristic of the fluidwithin the flow path.

The sensor may generate a signal responsive to one or more selectedcharacteristic of the fluid in one of the fluid flow path, with thesuspension treatment device including a controller adapted to receivethe sensor signal and to control the treatment device in responsethereto. In the situation where the third fluid flow path communicateswith the human subject, and the treatment device is adapted to addanticoagulant to the blood in the first fluid flow path, the selectedcharacteristic may include the hematocrit of blood in the first fluidflow path. In that setting, the controller may control the addition ofanticoagulant into the first fluid flow path to prevent too muchanticoagulant from being returned to the donor or patient, because, asis well known excess anticoagulant flow to the donor or patient may havedeleterious consequences.

The signal from the sensor and the control of the treatment device isnot limited, however, to the safety of the human subject. The controllermay, for example, in response to the signal control the treatment deviceto withdraw a constituent of desired quality, to withdraw a constituentof desired quantity, to withdraw a constituent that is depleted of anundesired component, or to withdraw a selected minimum quantity ofconstituents, such as platelets, red cells or plasma, or to withdraw acertain amount of constituent in a maximum or minimum procedure time.

In a more specific embodiment of the present invention, the MEMSsensor(s) or other MEMS devices are located on a common disposablecarrier or cassette. The carrier includes internally defined fluid flowpassageways that may be selectively opened or closed by macro or MEMSscale valves to control flow of fluid to the sensors in response tocontrol signals from the device controller. The carrier is preferablyadapted to interfit with a reusable reader/controller which cooperateswith the MEMS devices located in the cassette to provide a signalresponsive to the sensed characteristic, which signal may be used tooptimize the treatment procedure or to identify the sensedcharacteristic for later association with or labeling of the collectedblood product, or to control the flow of fluid through the cassette.

Although the carrier may take several different forms, in one form of acassette, it is comprised of a rigid plastic base that mounts aplurality of MEMS sensors or other MEMS devices such as valves or pumps,and has preformed passageways defined in the base with fluid flowcontrol valve modules located to control the flow of selected fluid tothe desired MEMS sensor. The cassette may include preformed openpassageways that are closed by a resilient membrane which overlies oneside of the cassette and is sealed to the passageway walls (eithertemporarily by pressure exerted by the reader or permanently by solventor sonic bonding) to close the passageways. The membrane may cooperate,such as by mechanical or pneumatic actuation, with the valve modules tocontrol the flow of fluid through passageways in the MEMS cassette.

The present invention is not limited to a particular type of MEMS sensoror to a particular principle of operation. The MEMS devices useful inthe present invention may be static or dynamic, purely mechanical,biomechanical or electromechanical. They may also include opticalcomponents, and they may be dry or used in combination with liquidreagents or other liquids.

One type of MEMS sensor that holds promise for apheresis procedures is amicrocytometer in which particles, for example cells, or cell fragments,are fed through a narrow, microfluidic channel in single file. OtherMEMS sensors may be based, for example, on centrifugal microfluidicsanalysis employing a rotating compact disc that employs, for example, amicro-fluidics manifold and spectrophotometric cuvette formed on thesurface of the disc, which may be read by an optical disc reader.

Because certain MEMS devices may require special or separatesterilization procedures as compared to other MEMS devices, the presentinvention also contemplates that there may be more than one MEMS carrieror cassette. For example, MEMS employing reagents may require adifferent sterilization technique, such as ethylene oxide sterilization,as compared to purely mechanical or electromechanical,optical/mechanical or optical/electrical MEMS devices, which may besuitable for radiation or heat sterilization. There may also be otherreasons for having more than one MEMS cassette, including ease ofmanufacturing, ease of mounting or assembly on the treatment device, andthe like. In such case, the MEMS cassette may be attached to theremainder of the fluid circuit after sterilization, as by steriledocking or other sterile connection procedure.

Fluid may be pumped through the MEMS cassette by the peristaltic pumpsthat are typically employed on apheresis devices for moving blood andblood components through the tubing set or, alternatively, the MEMScassette itself may include macro and/or MEMS-scale pumps forcirculating fluid through the MEMS cassette and to the desired MEMSsensor. Similarly, liquid flow through the cassette may be controlled byMEMS scale valves, or by macro scale valves such as those employed inthe fluid flow control modules of the Amicus apheresis centrifugemarketed by Baxter Healthcare.

Additional aspects and features of the present invention are set forthin the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is schematic flow chart of a suspension treatment systemembodying the present invention.

FIG. 2 is a software/data flow chart for a control and data flow systemthat may be employed in the present invention.

FIG. 3 is a perspective view of a reusable suspension treatment device,specifically an apheresis device, embodying the present invention.

FIG. 4 is an enlarged perspective view of a portion of the device ofFIG. 3, showing the reader/controller for a MEMS cassette or carrier.

FIG. 5 is a plan schematic of a disposable fluid circuit, including aMEMS cassette or carrier, for use with the device of FIG. 3 andemploying the present invention.

FIG. 6 is an exploded perspective view of a MEMS cassette or carrierthat may be used in the disposable fluid circuit of FIG. 5, embodyingthe present invention.

FIG. 7 a is a top view of the assembled MEMS cassette of FIG. 6.

FIG. 7 b is a side view of the MEMS cassette of FIG. 7 a.

FIG. 8 is a perspective view of the reader/controller for the MEMScassette.

FIG. 9 is an enlarged perspective view of the device of FIG. 3,embodying an alternative MEMS cassette reader/controller.

FIG. 10 is an exploded perspective view of a MEMS cassette that may beused with the reader/controller shown in FIG. 9.

FIG. 11 is a rear perspective view of the assembled MEMS cassette ofFIG. 10, illustrating macro-scale valve modules for fluid flow control.

FIG. 12 is an enlarged perspective view showing the interfit between theMEMS cassette of FIG. 10 and the reader/controller of FIG. 9.

FIG. 13 is a schematic view of MEMS microcytometer that may be used inthe present invention.

FIG. 14 is a view of the microcytometer of FIG. 13, illustrating thefocusing of blood cells using sheath flow.

FIGS. 15 a and 15 b are cross-section views of a bistable valve that maybe used in the MEMS cassette of the present invention.

FIG. 16 is a top plan view of an alternative MEMS cassette embodying thepresent invention, which includes fluid pumping chambers for pumpingfluid through the cassette.

FIG. 17 a is a plan view of a compact disc employing a microfluidicmanifold and a spectrophotometric cuvette.

FIG. 17 b is an elevational view of a reader for the compact disc ofFIG. 17 a.

FIG. 18 a is a plan view of a blood component storage container having aMEMS sensor mounted in or carried on the container wall for accessingthe contents.

FIG. 18 b is a plan view of the container of FIG. 18 a with a reader forreading the MEMS sensor.

DETAILED DESCRIPTION OF DRAWINGS

Turning now to a more detailed description of the drawings, FIG. 1 is aflow chart illustrating a treatment system embodying the presentinvention. Although the flow chart in FIG. 1 is in the context of ablood apheresis system, the flow chart and the steps indicated thereinhave application to other suspension treatment systems as well.

Before describing the treatment system in more detail, it should beunderstood that the flow chart is intended to reflect general systemfeatures and functions, and not necessarily the system structure. Forexample, it should be understood that features shown in a single box orgrouping of the flow chart may represent what are actually two or morephysical modules or structures in the actual product, and more than onebox or grouping in the flow chart may be a single physical module orstructure in the final product. The purpose of the flow chart is simplyto illustrate one embodiment of an overall system and function, and notto limit the actual physical structure.

As applied to apheresis, the system in FIG. 1 includes an apheresisdevice 50, such as a centrifuge, spinning membrane separator or otherapheresis device or instrument, and an instrument or device controlsystem 52. The control system 52, which may comprise a programmablemicroprocessor, performs a variety of control and monitoring functionsfor carrying out an apheresis procedure. It receives and sends dataregarding various initial, in-process and final product characteristics,it controls the fluid flow through the system, it controls the operationof the apheresis device and it tracks and stores data for labeling thefinal product or for communicating with data storage media associatedwith the container in which product is collected during the apheresisprocedure.

In the system shown in FIG. 1, whole blood is collected from a donor 54,such as a healthy adult human. The flow of blood (and other liquids suchas priming solution and anticoagulant) through the system is controlledby a fluid management module 56. In accordance with the presentinvention, one or more characteristics of the blood flowing into thesystem may be sensed by one or more MEMS sensors. For example, aninitial sample of the whole blood, before processing, may brought intocontact with one or more initial condition MEMS sensors 58 for sensingor measuring red cell count, platelet count, lipid level, blood type ormarkers representative of pathogen (viral or bacteria) presence. As usedhere, “sensor” or “sensing” is used broadly and includes detecting,measuring, monitoring, analyzing, characterizing, sampling and any othertests or analysis that may be desired.

Data from the initial conditional sampling, typically in the form of anelectrical signal, may be fed back to the control system 52 forpurposes, for example, of controlling the fluid management module or theapheresis separation process or for tracking or storing informationrelating to the sensed characteristic for later association with thecollected product. For example, data as to blood type may be saved forrecording on a machine readable or human readable data storage mediacarried by the container for the collected product, such as adescriptive label, bar code or electronic memory device. Data regardinginitial platelet count may be used, for example, to optimize theapheresis procedure to minimize procedure time, to maximize the amountof platelets collected or to better assure collection of a certainminimum number of platelets.

The anticoagulated whole blood is directed by the fluid managementmodule to the apheresis device or instrument 50. There, the blood isseparated into one or more components, such as components nos. 1, 2 andup to “n” components. During the apheresis procedure, in-process datamay be sensed by one or more of the in-process condition MEMS sensors60, for detecting characteristics such as white cell count, red cellhematocrit and platelet density. Data from the in-process condition MEMSsensor(s) may be fed back to the control system 52, typically forcontrolling the apheresis process and/or fluid flow. The in-processcondition MEMS sensor may sample fluid one or more times during theprocedure, as desired. To provide periodic adjustment of the apheresisdevice or fluid flow throughout the apheresis procedure, a plurality ofMEMS sensors may be employed in the in-process sensing. These MEMSsensors may be activated by the control system to sense one or moreselected characteristic at selected time intervals throughout theprocedure or upon occurrence of certain triggering events, such as poweroutage, red cell spill over or other event.

The separated blood components not returned to the donor are directed tostorage containers 64, 66 and 68, respectively. It is not necessary, ofcourse, for the storage containers to be outside of the apheresisdevice. In the Baxter CS-3000® and Amicus® centrifuges, for example,blood components may be collected in containers that reside inside therotating centrifuge until the apheresis procedure is completed.

As one or more components are collected, one or more characteristics ofthe final collected product may be sensed by the MEMS final productcondition sensor(s) 62 and data relayed back to the controller 52. Thefinal product condition MEMS sensor 62 may be provided to sense one ormore characteristics of the collected product, such as white cell count,packed red cell hematocrit, platelet dose, pH, or gas (e.g., CO₂)partial pressure. The final product condition MEMS may feed data back tothe control system 52 for optimizing the apheresis procedure,controlling fluid flow and/or storing/tracking data for association withthe final collected product.

One of the benefits of certain aspects of the present invention is theproviding of a final product that is fully or partially characterizedaccording to the initial condition, in-process and/or final productcondition MEMS sensors, with the characteristics sensed being tracked orstored for association with the final product container, all occurringwith reduced human intervention and opportunity for error. For example,having received data from the various MEMS condition sensors 58, 60 and62, the instrument control system 52 may relay that data to a recorderor labeler 70, which records the data onto data storage media 72 carriedby the storage container. The data or storage media may be humanreadable, or machine readable (e.g., graphic or bar code), or acombination of both or other form. The recorder may, for example, printa label for attachment to the container, or transfer the data to amachine readable electronic storage device, such as a memory chip,carried by the container. The result is a blood component productcharacterized as needed, with reduced need for human intervention oropportunity for human error.

FIG. 2 is an outline of certain aspects of a programmable operationcontrol system. As shown there, the procedure process master controlmodule 74 may instruct (shown by dashed lines) various elements of thesystem to perform certain functions, and receive (shown by solid lines)data from one or more of those elements. For example, the master controlmay direct the sample pre-measurement module 76 to carry out certaininitial condition sensing. This may be carried out by opening a macro orMEMS-scale valve that directs incoming whole blood into contact with thedesired initial condition MEMS sensor 58. The information or dataregarding the sensed characteristic is then relayed back through thepre-measurement module to the master control module for storage or forlater association with the collected blood product.

Similar steps may be carried out as between the master control module 74and the in-process module 78 and in-process MEMS sensor(s) 60, and asbetween the master control module and the final product configurationmodule 80 and final product condition sensor(s) 62.

Information from the various MEMS sensors may then be relayed to therecorder/labeler 70 for associating the data with the final productcontainer. In one simple form, this may be by way of printing a labelfor attachment to the container or for printing the desired informationon a pre-attached label, although the present invention alsocontemplates that data could be transferred optically or electrically toan electronic data storage device (such as a non-volatile memory chip or“write once, read many times” storage device) attached to the finalproduct container. If the operator desires that only certain informationbe displayed with the product, the system permits less than all of thecharacteristics that are sensed to be displayed on or in connection withthe collected product.

FIG. 3 shows a biological suspension treatment device, and specificallyan Amicus® apheresis instrument 82 of the general type made and sold byBaxter Healthcare Corporation of Deerfield, Ill. The Amicus® separatoris described in detail in U.S. Pat. No. 5,462,416, which is incorporatedby reference, and that description will not be repeated in full here.

Briefly, the Amicus® separator is based on centrifugation principles,and separates blood components by reason of their different densities.The Amicus® separator is intended to work with a disposable, one-timeuse plastic tubing set, which will be described later, through whichblood and blood components flow during the apheresis procedure.

The Amicus® separator includes a base portion, generally at 84, a fluidmanagement and sensor panel area 86, and a display screen and touchcontrol panel 88. The machine base 84 contains the rotating centrifugechamber drive hardware and control electronics. The centrifuge chamberis accessible through a drop-down front door 90 for loading and removingthe disposable tubing set.

The fluid management and sensor panel includes three pump and valvestations, each of which has a pair of peristaltic pumps 92 and adjacentflow control module 94 for pumping fluid through the system andcontrolling the direction of fluid flow. User information regarding theapheresis procedure is displayed on the display screen 88, which alsoincludes touch input capability for operator entry of information orcontrol commands prior to and during the apheresis procedure.

In accordance with a preferred version of the present invention, theMEMS sensors and other devices are mounted on a single MEMS carrier orcassette 96 (FIG. 5), which is part of the disposable fluid circuit andintended for one-time use only. The apheresis instrument 82 (FIG. 3)includes a MEMS cassette reader/controller 98 into which the MEMScassette is mounted when the disposable fluid circuit is installed onthe instrument. The reader/actuator 98 cooperates with the MEMS cassettefor reading or transferring data from the MEMS sensors on the cassetteand for controlling flow of fluid through the MEMS cassette and to thedesired MEMS sensor or other MEMS device.

The MEMS cassette reader/controller shown in FIG. 3, and shown in largerview in FIG. 4, employs a base 100 adapted to receive the MEMS cassetteand a door 102 pivotally mounted on the base for closing over thecassette to block out ambient light and cooperate with optical,electronic or mechanical devices located in the base portion for readingor interpreting the MEMS sensors or other devices and/or for actuatingvalves or pumps located in the MEMS cassette.

FIG. 5 is a schematic view of a disposable one-time-use processingassembly or fluid circuit 104 embodying the MEMS cassette/carrier 96 ofthe present invention for use on the apheresis instrument shown in FIG.3. A detailed description of the disposable fluid circuit may be foundin U.S. Pat. No. 5,462,416, which was previously incorporated byreference, and will not be repeated here.

The processing assembly 104 includes an array of flexible tubing thatforms the fluid circuit through which blood and blood components flow.The fluid circuit conveys liquid to and from a processing chamber 106that is mounted in the rotating centrifuge chamber during use. The fluidcircuit includes a number of containers 110 a-f that fit on hangers onthe centrifuge assembly to dispense and receive liquids during theapheresis process.

The fluid circuit 104 also includes one or more in-line fluid controlcassettes 112, which are not to be confused with the MEMS cassette(although the fluid control cassettes could also include MEMS sensors orother MEMS devices and thus incorporate features of the presentinvention, if desired). FIG. 5 shows three such cassettes designated 112a, 112 b and 112 c. The cassettes serve in association with the pump andvalve stations on the centrifuge assembly to direct liquid flow amongthe multiple liquid sources and destinations. During a blood processingprocedure the cassettes centralize the valving and pumping functions tocarry out the selected procedure. Further details of these functions aredescribed in the above mentioned U.S. Pat. No. 4,562,416.

A portion of the fluid circuit 108 leading between the cassettes 112 a-cand the processing chamber 106 is bundled together to form an umbilicus114. The umbilicus links the rotating parts of the processing assembly(principally the fluid management processing chamber) with thenon-rotating, stationary parts of the processing assembly (principallythe cassettes and containers and fluid circuit tubing and MEMS carrieror cassette). The umbilicus links the rotating and stationary parts ofthe processing assembly without using rotating seals, by employing thewell known one-omega two-omega principle, which has long beensuccessfully used in the CS-3000® centrifuge marketed by BaxterHealthcare Corporation.

In the illustrated and preferred embodiment, the fluid circuit 104pre-connects the processing chamber 106, the containers 110, the fluidcontrol cassettes 112 and the MEMS carrier/cassette 96. The assemblythereby preferably forms an integral pre-assembled sterile unit,although it is recognized that if separate sterilization is required forthe MEMS cassette, it may require subsequent attachment, such as bysterile connection procedure, to the remainder of the fluid circuit.

During a typical dual needle platelet collection procedure, whole bloodis drawn into an inlet needle 116 and combined at a junction 118 withanticoagulant such as ACD, which is pumped from the ACD container 110 d,through fluid control cassette 112 a and from there into theseparation/processing chamber 106. In the separation chamber, plateletrich plasma is separated from packed red cells, and each is withdrawnfrom the separation chamber. The platelet rich plasma is withdrawnthrough the umbilicus 114 upwardly through cassette 112 c and then,after passing through an optical sensor, returned to a collectionchamber in the centrifuge. There, platelet concentrate is separated fromthe platelet rich plasma, and platelet-depleted or platelet-poor plasmais withdrawn from the collection chamber and collected in aplatelet-poor plasma storage container 110 c and/or returned to thedonor, with red cells through fluid control cassette 112 a and returnneedle 117. Although illustrated as a dual needle set, the presentinvention is equally applicable for a single needle fluid circuit of thetype also previously sold by Baxter Healthcare Corporation for use onthe Amicus® centrifuge.

In accordance with the present invention, as illustrated in FIG. 5, thefluid circuit 104 includes at least one MEMS cassette or carrier 96. Asshown in FIG. 5 for purposes of illustration and not limitation, theMEMS cassette 96 is shown having five fluid connections. The number ofconnections, however, depends on the fluid characteristics to be sensed,and fewer fluid connections may suffice for many blood-relatedapplications, as will be discussed later.

As illustrated in FIG. 5, the MEMS cassette 98 has a fluid inlet 120connected to the packed red cell line. Fluid in this line may bemonitored by MEMS sensors to determine the packed red cell hematocritfor the purpose, for example, of optimizing the separation procedure.

MEMS cassette fluid inlet 122 is connected to the whole blood inletline. Fluid from this line may be sensed by MEMS sensors, for example,to determine any of the initial condition data such as red cell count,platelet count, lipid level, blood type or the presence of a pathogen(viral or bacteria) indicator or marker.

The next fluid entry inlet line 124, is shown communicating to theplatelet rich plasma line. This may be used to perform in-processanalysis of white cell count, red cell hematocrit, platelet density andthe like.

Fluid connection 126 is connected to the platelet-depleted plasma line.MEMS sensors associated with this connection may be used to sense any ofthe desired final product characteristics of the plasma. Similarly,fluid connection 128 is attached to the platelet concentrate collectiontubing for MEMS sensing of one or more of the final characteristics ofthe platelet concentrate, such as platelet dose or density, white cellcount, platelet size, and the like.

A MEMS cassette or carrier 98 as presently contemplated is depicted ingreater detail in FIG. 6. As shown there, the cassette includes a rigidMEMS holder or support 130, a plurality of MEMS sensors or other MEMSdevices 132, front cover 134 and membrane backing 136. The holder orsupport 130 is preferably made of rigid plastic or other suitablematerial. A plurality of passageways 138 for fluid flow are provided inthe MEMS holder, for communicating the desired fluid to the desired MEMSsensor or other device. As illustrated in FIG. 6, three such fluidpassageways 138 are shown for initial condition, in-process, andfinished product characteristic sensing. The passageways are pre-formedinto the MEMS holder, and communicate with three arrays of MEMSdevice-receiving areas 140, which are adapted to receive the desiredMEMS sensors or other devices. The center fluid passageway communicateswith two rows of MEMS device receiving areas that flank the passageway.The other two passageways communicate with a single row of MEMS devices.The size of the array and number of MEMS sensors or other devices may bevaried as needed for a given treatment procedure to provide the desiredsensing capability. For those MEMS sensors or other devices that requirean electrical power source, the rigid holder may include a plurality ofelectrical contacts 142. Embedded or embossed electrical leads in theholder may extend between the contacts and the appropriate areas 140 formounting MEMS sensors or other devices that require a voltage source.

The MEMS holder and MEMS sensors/devices are contained beneath the clearcover plate 134, which is sealed to the holder 130, as by adhesive,sonic or solvent bonding, to form the passageways 138. The clear coverallows for the transmission of light to or from associated optical lightsources or receivers in the MEMS cassette reader. The flexible membrane196 attached to the underside of the MEMS holder allows for actuation ofvalves, pumps or other devices associated with the MEMS cassette, asdescribed in more detail later.

Turning to FIG. 7A, which is a plan view of the MEMS cassette or carrier98, the initial condition analysis sample line 144 communicates with afirst fluid passageway 138 a in the MEMS cassette that communicates witha plurality of MEMS sensors for sensing viral or pathogen markers (e.g.,a DNA analysis that may reveal the presence of an unwanted virus orbacteria), blood type, lipid level, platelet count and red cell count.The inlet to each MEMS sensors may be controlled by a valve 141, whichmay be macro-scale valve that controls flow of the initial fluid to theMEMS sensor or by MEMS-scale valves, which are available from a varietyof sources using various principles, such as surface tension, flexingmembranes or the like. It is contemplated that the initial conditionline would communicate, in an apheresis procedure, with the whole bloodinlet line. Additionally, although the passageways 138 are shown ashaving closed ends, the passageways may also continue through thecassette and return to the fluid circuit so that, for example, thesample lines are receiving a constant throughput of the fluid to beanalyzed.

The next inlet line is the in-process analysis sample line 146, whichcommunicates with the fluid flow passageway 138 b in the MEMS cassettefor sampling various characteristics of the fluid while the apheresisprocess is carried out. For example, the in-process fluid may flowthrough the center passageway 138 b to platelet density MEMS sensors,red cell MEMS sensors and MEMS sensors for counting the number of whitecells. The in-process flow line may be attached to the platelet-richplasma line, the packed red cell line or, if desired, with theprocessing chamber itself.

The final product analysis sample line 148 communicates with the thirdpassageway 138 c in the MEMS cassette for determining final productcharacteristics, such as partial pressure of CO₂, the pH, the plateletdensity, hematocrit or white cell count. It is anticipated that thisfinal product sample line would be connected to the flow linecommunicating with the final product collection container, althoughother connection sites, such as the processing chamber itself, arewithin the scope of this invention.

Although the characteristics described above are these that may bedetermined in the platelet collection procedure, the user may select orthe manufacturer may employ different MEMS sensors with differentobjectives or for sensing different characteristics, as desired.

As shown in FIG. 8, in use, the MEMS cassette or carrier 96 ispreferably mounted within a recessed area in the base 100 of the MEMScassette reader/controller 98. For MEMS devices employing opticalread-out, the base preferably includes an array of light emitting fibersor diodes 150 in registration with the appropriate MEMS devices, and thedoor 102 may include an array of light collectors or receivers 152 inregistration with the MEMS devices for the purpose of reading theoptical transmission, reflection or refraction by the particular MEMSsensor. The base and/or door also include electrical contacts 153 forconnecting with electrical contacts 142 of the cassette for MEMS needingan electrical voltage source. Therefore, it is apparent that the presentinvention is not limited to a particular type of MEMS sensor or deviceor to MEMS sensors or devices operating on a particular principle.

One example of a MEMS sensor for use in the present invention isillustrated in FIG. 13. The MEMS sensor shown there is a MEMSmicrocytometer 149, and is believed to have particular promise forcell-related applications. As may be seen there, the microcytometerincludes a light source 150 for emitting light, such as coherent laserlight, at a single file stream of components, such as cells which may bereceived from the initial condition, in process or final condition flowlines. Light receivers 152 and 154, receive reflected and refractedlight from the particles which, in turn, is used to count orcharacterize the cells flowing through the line, such as by cell type,cell density or number of cells. Fluorescence detection and lightscattering can be used to count and characterize the cells. Suchdetection may also be combined with immunossays techniques to detect andcharacterize antibody coated beads and antibody-antigen complexes. Thistype of MEMS sensor has been previously described by, and may beavailable from Micronics, Inc., of Redmond, Wash.

As shown in FIG. 14, the microcytometer 149 employs a micro-fluidicchannel 151 in which fluid flowing in a sheath flow arrangementresulting from liquid flow from the intersecting flow channels 153 formsthe cells into single file for analysis. Accordingly, it is within theconcept of the present invention that the MEMS cassette may also includeadditional fluid channels 153, as appropriate, for receiving liquids orgases (such as saline, water, reagents, or other liquids or gases) thatmay be used in connection with the MEMS sensors.

Another MEMS device that may be suitable for application in the presentinvention is a MEMS sensor based on centrifugal microfluidics analysis.One or more small rotating compact discs may be mounted in the MEMScassette, which disc may be read by an optical disc reader. The discemploys, for example, a micro-fluidics manifold and spectrophotometriccuvette formed on the surface of the disc. FIG. 17 diagrammaticallydepicts such a device, which has been proposed by and may be availablefrom Gamera Bioscience of Medford, Mass.

Microfluidic mixing devices, capillary connectors employingmicrochannels, and membrane micro-valves available from TMP of Enscheda,Netherlands, and thin-walled compliant plastic structures, micro-fluidiccircuits, silicone button pneumatic actuators and micro-valves asdisclosed by Lawrence Livermore National Laboratory at the Jul. 15-16,1999 Knowledge Foundation conference on Novel Microfabrication optionsfor Biomems, in San Francisco, Calif., are but a few of other MEMSdevices that may be incorporated into the MEMS cassette of the presentinvention.

As noted earlier, the MEMS cassette may include macro-scale valves, forexample, as used in the Baxter Amicus® separator for controlling flowthrough the fluid circuit module sets. These valves and their operationis described in more detail in previously cited U.S. Pat. No. 5,462,416.However, the MEMS cassette may also employ MEMS-scale valves 141, asillustrated in FIG. 7 a.

A wide variety of MEMS-scale valves are available. For example, FIGS. 15a and 15 b show a bi-stable valve 156 employing a membrane 158 thatflexes between a closed position, blocking inlet passageway 160 as shownin FIG. 15 a and an open position as shown in FIG. 15 b allowing flowbetween the inlet passageway and outlet passageway 162. The valvepresumably opens when the pressure in the valve chamber exceeds athreshold amount, at which time the membrane moves from the stableclosed position to the stable open position. The valve moves to thestable closed position when the pressure in the valve chamber dropsbelow a certain threshold value, causing the membrane to move from thestable open position to the stable closed position. Such a bistablemicrovalve was described by the Institute for Mikrostukturtechnik, atthe July, 1999 “Novel Microfabrication Options for Biomems, Technologies& Commercialization Strategies” conference sponsored by the KnowledgeFoundation. This is but one example of a MEMS scale valve that may beused in the MEMS cassette. It is also known to use micro-channels andsurface tension to form MEMS scale valves, with the valve opening whenfluid pressure exceeds a certain threshold to overcome the effects ofsurface tension. Such valves may also find use in a MEMS cassettes ofthe type disclosed here.

An alternative design for the MEMS carrier or cassette and the cassettereader/controller is shown in FIGS. 9-11. As shown in FIG. 9, a cassettereader/controller 164 comprises a pair of upstanding walls 166 defininga MEMS cassette-receiving slot between them. One wall has a functionsimilar to the base 100 of the prior embodiment and the other wallfunctions in a manner similar to the door of the prior embodiment. Inother words, one wall includes an array of light emitting fibers, diodesor the like, and any appropriate electrical contacts for cooperationwith the MEMS devices in the MEMS cassette. The facing wall includes anarray of light receivers for cooperating with the MEMS sensors and forreading the characteristics sensed. As before, one of these upstandingwalls may also include micro-scale valves for actuating or controllingflow through the MEMS cassette, or the MEMS cassette may includeMEMS-scale valves for controlling fluid.

FIGS. 10-11 depicts an alternative MEMS cassette 168 for use withreader/controller 164. The MEMS cassette 168 includes a base 170 havingpreformed fluid passageways 172 and pre-formed MEMS receiving ormounting areas 174 that may be connected to the passageways as desiredfor allowing fluid flow from the passageway to the MEMS sensor. As maybe seen in FIG. 10, the three fluid pathways extend fully through thebase from inlets 176 to outlets 178. A clear 180 cover is mounted on oneside of the base and a flexible membrane 182 on the other side of thebase.

As shown in an underside view, in FIG. 11, valve module areas 184 areprovided in the cassette which may be opened or closed by macro-scalevalve members which depress the flexible membrane to contact and closeagainst a valve module to block flow between the passageway and MEMSdevice or, upon release, to open a particular valve module to fluidflow. The valve opening and closing arrangement is preferably comparableto that already employed in the Baxter Amicus® centrifuge, which isdescribed in detail in the U.S. Pat. No. 5,462,416.

As illustrated in FIG. 12, this alternative embodiment of the MEMSreader 164 and cassette 168 permits very easy loading of the cassetteduring installation of the disposable by sliding the cassette downwardlybetween the upstanding walls 166 of the MEMS cassette reader/controller.

FIG. 16 illustrates another embodiment of a MEMS cassette or carrier 186in accordance with the present invention. The earlier describedcassettes rely on pressure within the tubing set (created by peristalticpumps 92) for moving the selected fluid into and through the MEMScassette. However, the MEMS cassette may itself have pumping chambersfor moving fluid through the cassette and, indeed, through the tubingset, if desired. FIG. 16 shows such a MEMS cassette 186.

As illustrated in FIG. 16, MEMS cassette 186, comparable to previouslydescribed embodiments, includes three internal passageways 188communicating with inlet flow tubing for sensing initial condition,in-process and final condition characteristics. In the FIG. 16embodiment, however, each passageway also communicates with a respectivepumping chamber 190. The pumping chamber preferably has one wall defineda flexible membrane bonded to one side of the cassette. Flexing of themembrane by mechanical or pneumatic pressure alternatively reduces andincreases the size of the chamber, resulting in a pumping action. Inletand outlet valves 192 at each end of the pumping chamber, which arealternatively opened and closed, control the direction of flow throughthe pump. As pointed out earlier, this pumping may be used only to movethe desired fluid through the MEMS cassette or may also be used to movefluid through the entire disposable fluid circuit, if desired.

FIG. 18 a shows a blood component container 194 with a MEMS sensor 196carried by or embedded in the wall of the container for sensing aselected characteristic of the blood component in the container. TheMEMS sensor may be adapted to access the container contents through afrangible part of the container wall or through a piercing memberassociated with the sensor, and may be adapted to test for bacterialcontamination and/or pH of the stored blood component. This would haveparticular application in sensing the blood component just beforeadministration to a patient to assure that the pH and bacteria levelsare acceptable.

After a suitable assay period required by the MEMS sensor, the resultsmay be read directly from the MEMS sensor. Alternatively, the MEMSsensor may be read by a reader 198 such as an automated optical,magnetic or electronic device, suitable for the particular MEMS sensormounted on the bag.

Although described in terms of one or more specific embodiments, thepresent invention is not limited to the specific structures disclosedfor illustrative purposes, and includes such changes or modifications asmay be apparent to one skilled in the field upon reading thisdescription.

1. A biological suspension processing system comprising: a bloodtreatment device for treating one or more components of a biologicalsuspension; a human subject; a first fluid flow path, wherein said firstfluid flow path is in continuing, direct communication with the vascularsystem of the human subject and the treatment device for introducingblood from the human subject into the treatment device; a second fluidflow path communicating with the treatment device for withdrawing aconstituent of the blood from the treatment device; a third fluid flowpath communicating with the treatment device for withdrawing anotherconstituent of the blood from the treatment device; at least onemicroelectromechanical sensor communicating with one of said fluid flowpaths for sensing either a biological or a chemical characteristic ofthe fluid within the flow path while said first fluid flow path is incontinuing, direct communication with the vascular system of the humansubject and a controller adapted to receive signals from said sensor andcontrol the blood treatment device in response thereto.
 2. The system ofclaim 1 in which the sensor generates a signal responsive to one or moreselected characteristics of the fluid in one of the fluid flow paths. 3.The system of claim 2 in which the third fluid flow path communicateswith the human subject, the treatment device is adapted to addanticoagulant to the blood in the first fluid flow path, the selectedcharacteristic includes the hematocrit of blood in the first fluid flowpath, and the controller controls the addition of anticoagulant into thefirst fluid flow path.
 4. The system of claim 2 in which the controllercontrols the treatment device in response to the signal to avoid one ormore deleterious consequences to the human subject.
 5. The system ofclaim 2 in which the controller controls the treatment device inresponse to the signal to withdraw a constituent of desired quality. 6.The system of claim 2 in which the controller controls the treatmentdevice in response to the signal to withdraw a constituent of desiredquantity.
 7. The system of claim 2 in which the controller controls thetreatment device in response to the signal to withdraw a constituentthat is depleted of an undesired component.
 8. The system of claim 7 inwhich the undesired component is white cells.
 9. The system of claim 2in which the controller controls the treatment device in response to thesignal to withdraw a desired constituent.
 10. The system of claim 9 inwhich the desired constituent is platelets.
 11. The system of claim 9 inwhich the desired constituent is red cells or plasma.
 12. The system ofclaim 2 in which the sensor senses platelets and the controller controlsthe treatment device to withdraw a selected minimum quantity ofplatelets.
 13. The system of claim 1 further comprising a fluidmanagement module carried by the first fluid flow path between thevascular system of the human subject and the treatment device, saidfluid management module adapted to receive blood from the vascularsystem of the human subject via the first fluid flow path and controlthe amount of blood introduced into the treatment device.
 14. The systemof claim 1 further comprising a container communicating with the secondfluid flow path for receiving the withdrawn constituent, the systembeing adapted to provide tracking information for associating with thecontainer the particular characteristic sensed by at least one sensor.15. The system of claim 14 in which the system further comprises machinereadable or human readable data storage media carried by the container,the data storage media storing information regarding the particularcharacteristic sensed by at least one sensor.
 16. The system of claim 15in which the data storage media comprises a bar code label on thecontainer.
 17. The system of claim 15 in which the data storage mediacomprises an electronic data storage device.
 18. The system of claim 17in which the electronic data storage device has a non-volatilesemiconductor memory.
 19. The system of claim 15 in which the datastorage media comprises at least one icon carried by the container andrepresentative of the sensed characteristic.
 20. The system of claim 15in which the suspension includes one or more blood components and theblood component withdrawn is a cellular component, and the container isfor storing the cellular component withdrawn, and the data storage mediaincludes data regarding the type, quality, purity, quantity orconcentration of the cellular blood component in the container.
 21. Abiological suspension processing system comprising: a blood treatmentdevice for treating one or more components of a biological suspension; ahuman subject; a first fluid flow path, wherein said first fluid flowpath is in continuing, direct communication with the vascular system ofthe human subject and the treatment device for introducing blood fromthe human subject into the treatment device; a firstmicroelectromechanical sensor communicating with said first fluid flowpath for sensing an initial condition of the fluid within said firstfluid flow path while said first fluid flow path is in continuing,direct communication with the vascular system of the human subject, saidfirst sensor further generating a signal responsive to the initialcondition of the fluid in said first fluid flow path; a second fluidflow path communicating with the treatment device for withdrawing aconstituent of the blood from the treatment device; a secondmicroelectromechanical sensor communicating with said second fluid flowpath for sensing either an in-process condition or a final productcondition of the fluid within said second fluid flow path while saidfirst fluid flow path is in continuing, direct communication with thevascular system of the human subject, said second sensor furthergenerating a signal responsive to the in-process condition or finalcondition of the fluid in said second fluid flow path; and a controlleradapted to receive the first and second sensor signals and to controlthe treatment device in response thereto.
 22. The system of claim 21 inwhich the third fluid flow path communicates with the human subject, thetreatment device is adapted to add anticoagulant to the blood in thefirst fluid flow path, the selected characteristic includes thehematocrit of blood in the first fluid flow path, and the controllercontrols the addition of anticoagulant into the first fluid flow path.23. The system of claim 21 in which the controller controls thetreatment device in response to the first or second sensor signal toavoid one or more deleterious consequences to the human subject.
 24. Thesystem of claim 21 in which the controller controls the treatment devicein response to the first sensor signal to withdraw a constituent ofdesired quality.
 25. The system of claim 21 in which the controllercontrols the treatment device in response to the second sensor signal towithdraw a constituent of a desired quantity.
 26. The system of claim 21in which the controller controls the treatment device in response to thefirst or second sensor signal to withdraw a constituent that is depletedof an undesired component.
 27. The system of claim 21 in which theundesired component is white cells.
 28. The system of claim 21 in whichthe controller controls the treatment device in response to the signalto withdraw a desired constituent.
 29. The system of claim 28 in whichthe desired constituent is platelets.
 30. The system of claim 28 inwhich the desired constituent is red cells or plasma.
 31. The system ofclaim 21 in which the sensor senses platelets and the controllercontrols the treatment device to withdraw a selected minimum quantity ofplatelets.
 32. The system of claim 21 further comprising a fluidmanagement module carried by the first fluid flow path between thevascular system of the human subject and the treatment device, saidfluid management module adapted to receive blood from the vascularsystem of the human subject via the first fluid flow path and controlthe amount of blood introduced into the treatment device.
 33. The systemof claim 21 further comprising a container communicating with the secondfluid flow path for receiving the withdrawn constituent, the systembeing adapted to provide tracking information for associating with thecontainer the particular characteristic sensed by at least one sensor.34. The system of claim 33 in which the system further comprises machinereadable or human readable data storage media carried by the container,the data storage media storing information regarding the particularcharacteristic sensed by at least one sensor.
 35. The system of claim 34in which the data storage media comprises at least one icon carried bythe container and representative of the sensed characteristic.
 36. Thesystem of claim 34 in which the suspension includes one or more bloodcomponents and the blood component withdrawn is a cellular component,and the container is for storing the cellular component withdrawn, andthe data storage media includes data regarding the type, quality,purity, quantity or concentration of the cellular blood component in thecontainer.
 37. The system of claim 33 in which the data storage mediacomprises a bar code label on the container.
 38. The system of claim 33in which the data storage media comprises an electronic data storagedevice.
 39. The system of claim 38 in which the electronic data storagedevice has a non-volatile semiconductor memory.
 40. A biologicalsuspension processing system comprising: a blood treatment device fortreating one or more components of a biological suspension; a humansubject; a first fluid flow path, wherein said first fluid flow path isin continuing, direct communication with the vascular system of thehuman subject and the treatment device for introducing blood from thehuman subject into the treatment device; a first microelectromechanicalsensor communicating with said first fluid flow path for sensing aninitial condition of the fluid within said first fluid flow path whilesaid first fluid flow path is in continuing, direct communication withthe vascular system of the human subject, said first sensor furthergenerating a signal responsive to the initial condition of the fluid insaid first fluid flow path; a second fluid flow path communicating withthe treatment device for withdrawing a constituent of the blood from thetreatment device; a second microelectromechanical sensor communicatingwith said second fluid flow path for sensing either an in-processcondition or a final product condition of the fluid within said secondfluid flow path while said first fluid flow path is in continuing,direct communication with the vascular system of the human subject, saidsecond sensor further generating a signal responsive to the in-processcondition of the fluid in said second fluid flow path; a third fluidflow path communicating with the treatment device for withdrawinganother constituent of the blood from the treatment device; a thirdmicroelectromechanical sensor communicating with said third fluid flowpath for sensing a final product condition of the fluid within saidthird fluid flow path while said first fluid flow path is in continuing,direct communication with the vascular system of the human subject, saidthird sensor further generating a signal responsive to the final productcondition of the fluid in said third fluid flow path; and a controlleradapted to receive the first, second, and third sensor signals and tocontrol the treatment device in response thereto.
 41. The system ofclaim 40 further comprising a fluid management module carried by thefirst fluid flow path between the vascular system of the human subjectand the treatment device, said fluid management module adapted toreceive blood from the vascular system of the human subject via thefirst fluid flow path and control the amount of blood introduced intothe treatment device.
 42. The system of claim 40 further comprising acontainer communicating with the second fluid flow path for receivingthe withdrawn constituent, the system being adapted to provide trackinginformation for associating with the container the particularcharacteristic sensed by at least one sensor.
 43. The system of claim 40in which the system further comprises machine readable or human readabledata storage media carried by the container, the data storage mediastoring information regarding the particular characteristic sensed by atleast one sensor.
 44. The system of claim 43 in which the data storagemedia comprises a bar code label on the container.
 45. The system ofclaim 44 in which the electronic data storage device has a non-volatilesemiconductor memory.
 46. The system of claim 43 in which the datastorage media comprises an electronic data storage device.
 47. Thesystem of claim 43 in which the data storage media comprises at leastone icon carried by the container and representative of the sensedcharacteristic.
 48. The system of claim 43 in which the suspensionincludes one or more blood components and the blood component withdrawnis a cellular component, and the container is for storing the cellularcomponent withdrawn, and the data storage media includes data regardingthe type, quality, purity, quantity or concentration of the cellularblood component in the container.